Introduction

Atenolol is a selective β1 receptor antagonist, a drug belonging to the group of beta blockers, a class of drugs used primarily in cardiovascular diseases.

Chlorthalidone is a diuretic drug used to treat hypertension, originally marketed as Hygroton in the USA. It is described as a thiazide diuretic. It is often used in the management of hypertension and edema.

With this application note we illustrate how silica gel G 254 plates are suitable for analysis of Atenolol and Chlorthalidone in a combination drug following the experimental conditions per the European pharmacopeia identification TLC test for Atenolol (version 9.0).

Atenolol

Chlorthalidone

Experimental Conditions

TLC Plate

Silica Gel 60G F254 20 x 20 cm

Injection volume

5 µL of each solution

Detection

UV @ 254 nm

Mobile Phase

18 M Ammonia and n-butanol 30:150 (v/v)

Plate development

Line the walls of chromatographic tank with filter paper. Pour into the chromatographic tank sufficient quantity of mobile phase Saturate the chromatographic tank replace the lid and allow to stand for 20-25˚C for 1 hr. Apply the prescribed volume of the solutions in sufficiently small portions to obtain bands at an appropriate distance from the lower edge.

When the solvent has evaporated from the applied spots place the plate in as vertical as possible close the tank and allow the plate to run for 15 cm .Remove the plate and dry the plate and observe under UV light at 254 nm

Diluent

Methanol

Development

15 cm

Drying

In air

Standard

1.0% (w/v) of atenolol in methanol and 0.25 % (w/v) of Chlorthalidone in methanol

Sample

Remove any film coating on the tablet powder and shake the quantity of powdered tablet containing 0.1 g of atenolol with 10 ml of methanol for 15 minutes and filter.

TLC Plate Development

Chromatogram

Spectrum for Altenolol

Spectrum for Chlorthalidone

Chromatographic Data (Standard Solution )

Compound

Rf

Area

1

Atenolol

0.24

25166

2

Chlorthalidone

0.68

38676

Altenolol

Chlorthalidone

Chromatographic Data (Sample Solution )

Compound

Rf

Area

1

Atenolol

0.24

22533

2

Chlorthalidone

0.69

31061

Standard Repeatability - Altenolol

STD 1

25045

STD 2

25166

STD 3

25453

STD 4

25092

STD 5

25346

Mean

25220.4

Standard Deviation

154.97

RSD (%)

0.6

Standard Repeatability - Chlorthalodine

STD 1

38676

STD 2

37752

STD 3

37102

STD 4

37598

STD 5

37899

Mean

37805

Standard Deviation

511.3

RSD (%)

1.4

Summary

The principal spot in the chromatogram obtained with the test solution and the two principal spots correspond in position, size and intensity to those of the principal spots in the chromatograms obtained with standard solutions.

The repeatability for Atenolol and Chlorthalidone standards, was 0.6 and 1.4 %, respectively.